1. Field of Invention
The present invention relates generally to one time programmable (OTP) memory, and more particularly to OTP memory that is fabricated using a Gate-Last High-K Metal Gate fabrication process.
2. Background Art
In the field of data storage, there are two general types of storage devices. The first type of storage device is volatile memory. Volatile memory loses stored information when power is removed from the volatile memory circuit. The second type of storage device is non-volatile memory. Non-volatile memory retains stored information even after power is removed from the non-volatile memory circuit. Some non-volatile memory designs permit reprogramming while other designs only permit one-time programming.
One time programmable (OTP) memory represents a type of non-volatile memory that may be programmed once, typically, by permanently programming a fuse to open a connection or by permanently programming an anti-fuse to close a connection.
Currently, the following kinds of fuses are utilized as eFuses: gate oxide breakdown, hot carrier, silicide fuse, interconnect metal fuse. The HKMG process allows for a high-K dielectric to replace the silicon dioxide gate dielectric that was used in previous generations of foundry technology. The use of the high-K dielectric allows for further miniaturization of micro-electrical components. Furthermore, the previous generations of fuses require a high amount of current in order of hundreds of microamps to blow.
Accordingly, what is needed is an eFuse that is compatible with a HKMG process that is conventionally utilized in 28 nm foundry technology. Additionally, it would be beneficial if the eFuse can be utilized by application of a low current level as compared to conventional eFuses.
The present invention will now be described with reference to the accompanying drawings. In the drawings, like reference numbers indicate identical or functionally similar elements. Additionally, the left-most digit(s) of a reference number identifies the drawing in which the reference number first appears.